Fabric made from conjugate yarns having enhanced absorbency

Abstract

In a preferred embodiment, the present process involves subjecting the nonwoven fabric both to an acidic treatment and to a caustic treatment, each of which erodes a portion of the components of the conjugate yarns. The acid treatment, given certain reaction kinetics, removes a portion of the polyamide element of the conjugate filament. The caustic treatment has a similar effect on the polyester element of the conjugate filament, making it more hydrophilic. The at least partial removal of the polyamide component, coupled with the increased hydrophilicity of the polyester component, results in a fabric having enhanced absorptive properties. In an alternate embodiment, treatments with only acid or only caustic solution may be employed.

We claim:  
     
         1 . A fabric comprising continuous conjugate filaments, each of said conjugate filaments further comprising at least a first filament material and a second filament material that are longitudinally separate into elementary filaments, wherein said first filament material is substantially resistant to acid degradation and said second filament material is susceptible to acid degradation, wherein said second filament material comprises a filament skeleton that has been at least partially reconfigured.  
     
     
         2 . The fabric of  claim 1  wherein said first filament material is a polyester-like material selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), and polylactic acid (PLA).  
     
     
         3 . The fabric of  claim 2  wherein said first filament material is polyethylene terephthalate (PET).  
     
     
         4 . The fabric of  claim 1  wherein said second filament material is a polyamide selected from the group consisting of nylon 6, nylon 6 6, nylon 1 1, and nylon 610.  
     
     
         5 . The fabric of  claim 4  wherein said second filament material is nylon 6.  
     
     
         6 . The fabric of  claim 1  wherein said fabric has a nonwoven construction.  
     
     
         7 . The fabric of  claim 1  wherein the reconfiguration of said second filaments comprises separation of the skeleton into at least two parts.  
     
     
         8 . The fabric of  claim 7  wherein the reconfiguration of said second filaments comprises separation of the skeleton into at least two parts, in which at least one part has been dissolved.  
     
     
         9 . The fabric of  claim 1  wherein the reconfiguration of said second filaments comprises removal of at least a portion of the skeleton.  
     
     
         10 . The fabric of  claim 9  wherein the reconfiguration of said second filaments involves removal of at least of portion of the skeleton due to dissolution.  
     
     
         11 . A fabric comprising continuous conjugate filaments, each of said conjugate filaments further comprising at least a first filament material and a second filament material that are longitudinally separable into elementary filaments, wherein said first filament material is a polyester and said second filament material is a polyamide, and wherein the relative percentage of said polyamide varies per unit of said fabric.  
     
     
         12 . The fabric of  claim 11  wherein the relative percentage of said polyamide varies from 0.1% to 80%.  
     
     
         13 . The fabric of  claim 11  wherein said polyamide is selected from the group consisting of nylon 6, nylon 6 6, nylon 1 1, and nylon 610.  
     
     
         14 . The fabric of  claim 13  wherein said polyamide is nylon 6.  
     
     
         15 . The fabric of  claim 11  wherein said first filament material is a polyester-like material selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), and polylactic acid (PLA).  
     
     
         16 . The fabric of  claim 15  wherein said polyester is polyethylene terephthalate (PET).  
     
     
         17 . A fabric comprising continuous conjugate filaments, which further comprise at least a first filament material and a second filament material that are longitudinally separable into elementary filaments, wherein said first filament material is a polyester and said second filament material is a polyamide, and wherein said nonwoven fabric has an absorption capacity of at least 5.5 ml/g.  
     
     
         18 . The fabric of  claim 17  wherein said nonwoven fabric has an absorption capacity of at least 6.25 ml/g.  
     
     
         19 . The fabric of  claim 17  wherein the nonwoven fabric has an absorption capacity of at least 7.0 ml/g.  
     
     
         20 . The fabric of  claim 17  wherein said polyamide is selected from the group consisting of nylon 6, nylon 6 6, nylon 1 1, and nylon 610.  
     
     
         21 . The fabric of  claim 20  wherein said polyamide is nylon 6.  
     
     
         22 . The fabric of  claim 17  wherein said polyester is selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), and polylactic acid (PLA).  
     
     
         23 . The fabric of  claim 22  wherein said polyester is polyethylene terephthalate (PET).  
     
     
         24 . A fabric comprising continuous conjugate filaments, which further comprise at least a first filament material and a second filament material that are longitudinally separable into elementary filaments, wherein said first filament material is a polyester having hydrolized ester groups and enhanced hydrophilic characteristics by having exposed said polyester to a basic solution and wherein said second filament material is a polyamide whose structure is eroded by having been exposed to an acidic solution.  
     
     
         25 . The fabric of  claim 24  wherein said basic solution comprises sodium hydroxide.  
     
     
         26 . The fabric of  claim 24  wherein said polyamide has a structure that has been eroded by having been exposed to said acidic solution, said acidic solution comprising paratoluene sulfonic acid.  
     
     
         27 . The fabric of  claim 24  wherein at least 50% of said polyamide is eroded by having been exposed to said acidic solution.  
     
     
         28 . The fabric of  claim 24  wherein said polyamide is selected from the group consisting of nylon 6, nylon 6 6, nylon 1 1, and nylon 610.  
     
     
         29 . The fabric of  claim 28  wherein said polyamide is nylon 6.  
     
     
         30 . The fabric of  claim 24  wherein said polyester is selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytriphenylene terephthalate (PTT), and polylactic acid (PLA).  
     
     
         31 . The fabric of  claim 30  wherein said polyester is polyethylene terephthalate (PET).